The Emergence of Networking Abstractions and Techniques in TinyOS

1. The Emergence of Networking Abstractions and Techniquesin TinyOS

2. Title The Emergence of Networking Abstractions and Techniques in TinyOS

3. Tranditional OS • Multi thread • Blocking I/O Model • Kernel / User area • No power limitaion

4. Sensor Network OS • Power limitation • Small memory • Restricted H/W • Wireless Commucation

5. TinyOS • Origin from Smart Dust project of US. Berkely • Embedded • Componente-based • Completely non-blocking

6. TinyOS: Design • Current and likely future design • Diverse implementation • Address the specific and unusual challenges

7. TinyOS: H/W • rene mote • Released in 2000 • 4MHz, 8kB flash, 0.5kB RAM, 10kBaud

9. TinyOS: H/W • mica • Released in 2002 • 4MHz, 128kB flash, 4kB RAM, 40kBaud

11. TinyOS: H/W • mica2 • Released in 2003 • 7MHz, 128kB flash, 4kB RAM, 40kBaud

13. TinyOS: H/W • iMote • Released in 2003 • 12MHz, 512kB flash, 64kB RAM, 460kBaud

15. TinyOS: Application • Habitat Monitoring • Great Duck Island • Vineyard in British Columbia • Keep energy consumption low

16. Great Duck Island

17. Great Duck Island

18. TinyOS: Application • Shooter Localization • Origin of bullet in an urban setting • A high sample rate and fine-grain time sync

19. Sensor Network-Based Countersniper System at Stanford Univ.

20. TinyOS: Application • Pursuer-Evader • Mote localization and advanced route

21. Network in TinyOS • Low bandwidth • Consumes majority of the active power • Issues • Discovery • Routing • Reliability • Congestion control

22. Single hop: Active Messages • rene Gray Components abstract hardware

23. Single hop: Active Messages • mica Gray Components abstract hardware

24. Single hop: Active Messages • mica2 Gray Components abstract hardware

25. Single hop: Active Messages • mica S-MAC Gray Components abstract hardware

26. Multi hop • Tree-based collection • Route or aggregate data to endpoint • Intra-networking routing • Data is transferred between in-network endpoints • And disseminate to entire region

27. Tree-Based Routing • Based on • A parent node ID • Hop-count or depth from the tree root • A node routes a packet by transmitting it with the parent • Until the packet reaches the root of the tree • AMROUTE, BLess, Surge, mh6, MultiHopRouter

28. Intra-network Routing • DSDV, AODV • Unicast routing to specific endpoints • GPSR • Node’s geographical locaion • Intra-network routing is uncommon in TinyOS • Except Pursuer-Evader

29. Broadcast and Epidemic Protocols • Broadcast • For reconfigure filter setting or radio transmit power • For distribute new version of TinyOS programs • Simple flooding protocol • Common, easily implemented • Epidemic algorithm • Epidemic only transmits when needed • Local suppression mechanisms can reduce redundant transmission: saving energy

30. Network Service: Power Management • TinyOS manages power management • Each service can be stopped • HPLPowerManagment Component put the processor into the lowest-power mode • TinyOS timer service can function in the extremely-low-power, power-save mode • Cross-layer control at a very low-level • HPLPowerManagement can switch the processor into various lower-power modes.

31. Time Synchronization • For combine a set of coincident readings from different location, need to establish the temporal consistency of data • TDMA-style media access protocols for slot coordination • Power-aware approaches to communication scheduling • Low-level time sync were unsuccessful • Get and set system time and time stamp message

32. General Abstraction • The AM abstraction • Stable since the earliest TinyOS • Tree-based routing(the Send and Intercept interfaces) • Route(Berkeley), HSN, AODV, DSDV() use this interface

33. Specialized Abstraction • Power management and Time synchronization • General abstractions of these services are very hard to get right • Requirements of applications vary dramitically • Accurate to within a few milliseconds with a small set of other nodes • Globally synchronized clock that is much less accruate

34. In-Flux Abstractions • Commonly found but changing between applications and H/W version • Epidemic propagation • Radio MAC • Channel activity, the use of control packet per data packet, backoff, link estimation

35. Absent Abstractions • Expected to find in TinyOS but that were absent in the code base • Distributed cluster formation • Incoming(receive) queues

36. Communication Scheduling and Snooping • Communication scheduling • To disabling the radio expect druing pre-arranged time • Snooping • Receiving packets that might not even be destined for a node • To acquire network neighborhood

37. Cross-Layer Control • Routing stacks share network neighborhood information between link state(low layer) and network layer(higher layer) • Avoiding duplicating data • Conserving RAM • Provision by the network stack of low-level information to a higher level • Avoid unnecessary communication

38. Static Resource Allocation • Allow buffer for the network, sensor, UART and the other OS services at complie-time • RAM is valuable in TinyOS

39. EmNets vs. the Internet • Networking Abstractions in sensor network differ from tranditional Internet abstractions • Resource constraints • Very different set of goal and principles • Sensor networks are • Homogeneous system • Application-specific and collaborative perpose • Every node is both a sensor and a router

40. Conclusion • Classify the most prominent abstractions in TinyOS • General, Special, In-flux, Absent • Find Several techqiunces • Closs-layer control • Static resource allocation • WSNs is drivend by • Power management • Limited resource • Real-time conistraints

41. David Culler